# Implementation of matplotlib function   
import matplotlib.pyplot as plt 
from matplotlib import collections, colors, transforms 
import numpy as np 
   
nverts = 50
npts = 100
   
r = np.arange(nverts) 
theta = np.linspace(0, 2 * np.pi, nverts) 
xx = r * np.sin(theta) 
yy = r * np.cos(theta) 
spiral = np.column_stack([xx, yy]) 
   
rs = np.random.RandomState(19680801) 
   
xyo = rs.randn(npts, 2) 
   
colors = [colors.to_rgba(c) 
          for c in plt.rcParams['axes.prop_cycle'].by_key()['color']] 
   
fig, ax1 = plt.subplots() 
   
col = collections.RegularPolyCollection( 
    7, sizes = np.abs(xx) * 10.0,  
    offsets = xyo,  
    transOffset = ax1.transData) 
  
trans = transforms.Affine2D().scale(fig.dpi / 72.0) 
col.set_transform(trans)  
  
ax1.add_collection(col, autolim = True) 
col.set_color(colors) 
   
fig.suptitle('matplotlib.axes.Axes.set_transform() function Example\n', fontweight ="bold") 
  
fig.canvas.draw() 
  
plt.show()